Grafting with double-layered polypropylene mesh for gap healing of mid-metacarpal superficial digital flexor tendon in Equus asinus: clinical and pathological evaluations

Abstract

Tendon injury is one of the most common causes of wastage in equine. The superficial digital flexor tendon (SDFT) gets affected the most, especially in the mid-metacarpal region. Several studies have focused on the grafting of severed SDFT, but no ideal grafting material has been approved for clinical application. The present study aimed to evaluate the grafting of the mid-metacarpal SDFT in donkeys with a double-layered polypropylene mesh clinically, ultrasonically, macro/microscopically. Clinically healthy adult donkeys (n = 24) were divided randomly and equally into two groups: control (C) and study (S) groups. Tenotomy was performed on all animals by excising a full-thickness segment from the mid-metacarpal SDFT. In the C group, a suture tenorrhaphy was performed. While in the S group, SDFT was grafted with the double-layered polypropylene mesh. The S group showed faster clinical improvements, and earlier appearance of normal newly formed tendinous tissue ultrasonically compared with the C group. Macroscopically, the grafted tendons showed a rapid restoration of normal color and consistency. Moreover, they had minimal peri-tendinous adhesions compared with the non-grafted tendons. Microscopically, the grafted tendons showed earlier vascularization and more mature collagen fibers compared with the non-grafted tendons. In the present study, we have succeeded to graft the gap of the mid-metacarpal SDFT of a donkey using the double-layered polypropylene mesh. This method is an economical way to accelerate the healing process of the SDFT and enhance the clinical recovery in donkeys.